In the present contribution we demonstrate a new testing cell, which allows simultaneous in situ optical and electrochemical investigations of passivation processes on zinc anodes in quiescent alkaline electrolytes. By combination of microscopy and galvanostatic impedance spectroscopy it was possible to detect the starting point of passive film formation, which has not been achieved so far. We found that formation of the so-called type 1 passive film is not dependent on the anodic current density. This passive film appears at electrode overpotentials of <0.15 V after an amount of zincate ions of approx. 8.2 • 10 -4 mol cm -2 has accumulated at the anode in a 30 wt% KOH electrolyte with 2 wt% ZnO at room temperature. Consequently, the passivation of zinc in quiescent electrolyte cannot be avoided even at very low dissolution currents. On the other hand, the so-called type 2 passive film appears below the first film due to direct oxidation of zinc. At overpotentials of ≥0.15 V the direct oxidation of zinc is favored and the potential-dependent type 2 passive film appears before type 1 film is formed.

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In the course of the energy transition, storage technologies are required for the fluctuating and intermittently occurring electrical energy. The vanadium flow battery (VFB) is an especially promising electrochemical battery type for megawatt applications due to its unique characteristics. This work is intended as a benchmark for the evaluation of environmental impacts of a VFB, providing transparency and traceability. It considers the requirements for an industrial VFB from the technical and electrochemical point of view. The system design is based on a net capacity of 8 MWh and a net power of 1 MW. This ex ante study is a cradle‐to‐grave life cycle assessment (LCA) for a VFB to identify, analyze, and evaluate the environmental impacts for a lifetime of 20 years. Moreover, potential environmental impacts of several subsequent life cycles of the emission‐intensive and long‐lasting vanadium electrolyte are evaluated. With a focus on the electrolyte, the extraction process of vanadium pentoxide is studied in detail for the first time. Consequently, recommendations for the design of the life cycle of VFBs and for comparative LCAs with other energy storage technologies can be derived. Based on this work, more detailed work can follow, which helps to estimate the recycling potentials and emissions more precisely. This article met the requirements for a gold‐gold JIE data openness badge described at https://jie.click/badges